Wiki Super Heavy/Starship - General Development Discussion

[FoverM]

Wing has benefits, such as cross range, more stability, and maneuverability. However, wing = weight and cost, especially when a vehicle is re-entering atmosphere from outside of LEO. Expensive and complex thermal protection systems will be needed, but at the same time, weight will need to be minimized. These are very complex thermal/structural problems to be solved, which is why most in the aerospace world aren't trying to duplicate the Space Shuttle orbiter unless cross range and runway landing are design requirements.

Yes ... and these aren't even "wings" in the sense they'll be used for lift. They're just for control on reentry, yet they're getting larger, adding more points of failure, thermal issues, etc. The prototypes are already significantly over the design mass.

I thought the Shuttle taught everyone that reusable second stages were a bad idea and that all that matters is usable mass in orbit. STS had huge mass to LEO but most of that mass, the Orbiter, came back home. Starship will be the same.

 

[Cosmacelf]

I thought the Shuttle taught everyone that reusable second stages were a bad idea and that all that matters is usable mass in orbit. STS had huge mass to LEO but most of that mass, the Orbiter, came back home. Starship will be the same.

The Shuttle taught us that half assing a second stage such that it required 6 months of refurbishment was a bad idea. That's what it taught us.

Elon is not making that mistake.

Also, the first stage is reusable, which is another major difference with the Shuttle.

 

[JohnSnowNW]

I thought the Shuttle taught everyone that reusable second stages were a bad idea and that all that matters is usable mass in orbit. STS had huge mass to LEO but most of that mass, the Orbiter, came back home. Starship will be the same.

The STS wasn't reusable as much as refurbishable. Starship is supposed to be actually reusable (comment only relevant before tonight's update).

 

[mongo]

Yes ... and these aren't even "wings" in the sense they'll be used for lift. They're just for control on reentry, yet they're getting larger, adding more points of failure, thermal issues, etc. The prototypes are already significantly over the design mass.

I thought the Shuttle taught everyone that reusable second stages were a bad idea and that all that matters is usable mass in orbit. STS had huge mass to LEO but most of that mass, the Orbiter, came back home. Starship will be the same.

Rewatch the old presentation Making Life Multiplanetary. Reusability is a necessity for lower cost (by 5x). Refueling in orbit is another 5x and requires reusable tankers.

Have you looked at the payload to LEO??? In reusable mode it was speced at 150 tons. Shuttle was less than 30 tons. Saturn 5 was 135 tons.

Stainless is mitigating a lot of the thermal issues, and they'll add tiles where needed. And where are you getting the over mass claim from?

 

[Grendal]

And delayed... Kinda normal for Elon these days... 15 minutes.

 

[ecarfan]

Start time keeps slipping...

 

[Nikxice]

I would not describe that statement by Bridenstine that way. I think it’s a slam on SpaceX and it’s over the line. Bridenstine is basically saying that SpaceX is not giving proper attention and resources to Crew Dragon but is instead focusing on Starship. Which strikes me as ridiculous. I’m sure that the Crew Dragon team is doing everything they can to accomplish their objectives and we have no evidence that resources are being diverted to Starship.

I agree. Earlier I was probably being to nice toward Bridenstine. His snide remarks likely stem from the culture existing inside the administration he works for.

 

[ecarfan]

The prototypes are already significantly over the design mass.

Please provide a source for that statement and explain how you know that is true. Because unless you are on the SpaceX Starship engineering team, you can’t know that.

 

[FoverM]

Rewatch the old presentation Making Life Multiplanetary. Reusability is a necessity for lower cost (by 5x). Refueling in orbit is another 5x and requires reusable tankers.

Have you looked at the payload to LEO??? In reusable mode it was speced at 150 tons. Shuttle was less than 30 tons. Saturn 5 was 135 tons.

Stainless is mitigating a lot of the thermal issues, and they'll add tiles where needed. And where are you getting the over mass claim from?

Here:

Elon Musk on Twitter

Mk1 is 200 mT, 80 mT over their 120 mT target.

Reusability is great where it makes sense, which is the first stage. Reusing the second stage inevitably brings in a bunch of aerodynamic issues (because you're basically doing a full reentry), limiting usable payload and increasing complexity/risk. The real revolution is in-orbit refueling via a depot. Starship Heavy, with a simple and inexpensive expendable second stage, would work wonders at this. It's a big, dumb rocket for hauling raw mass to LEO (e.g. propellant, in-space hardware, etc.). Segmenting the aerospace field is critical to the future. Right now, designers have to optimize the entire trip from the ground to the end target and that causes all sorts of compromises. Place a known target in LEO and the engineers can optimize the hell out of getting there. Mission engineers can start their designs from LEO will a full propellant load. What's the old saying, once you're in LEO, you're halfway to anywhere in the solar system?

 

[SMAlset]

It’s starting. Elon speaking. Looks cool at night.

Showing a recap of the SpaceX program. Have to say the Roadster launch was emotional to watch. Love all of them but that one in particular with the camera angles, earth in the background, and car with Starman and general message was just so moving.

 

[SMAlset]

Started speaking.

 

[PhantomX]

Rewatch the old presentation Making Life Multiplanetary. Reusability is a necessity for lower cost (by 5x). Refueling in orbit is another 5x and requires reusable tankers.

Have you looked at the payload to LEO??? In reusable mode it was speced at 150 tons. Shuttle was less than 30 tons. Saturn 5 was 135 tons.

Stainless is mitigating a lot of the thermal issues, and they'll add tiles where needed. And where are you getting the over mass claim from?

I would recommend anyone interested in this to calculate the recovery temperature at re-entry speed, and then compared it to capability of any steel alloy, or any metallic material. And I have a little bit of experience with these type of engineering challenges, so I thought I would share some questions

 

[SMAlset]

Most of discussion looks to be here: Falcon Super Heavy/Starship - General Development Discussion

 

[SMAlset]

Presentation by Elon ended but Q & A with Elon will start in about 5 minutes.

In the meantime here’s a photo shared of the 3 raptor engines:

 

[Grendal]

Back to 150 tons. I expect there will still be changes as the prototypes are tested and more finalized Starships are officially built. Maybe not as dramatic as there has been in the past. Elon seems pretty certain that this is the right direction.

 

[Grendal]

Presentation by Elon ended but Q & A with Elon will start in about 5 minutes.

Can that be seen? Or will it be private?

On the livestream...

 

[SMAlset]

Q & A starting now on SpaceX.com. For those late to this I assume it will be available to re-watch on their site (both presentation and Q & A) like launches carried there. On YouTube as well.

 

[ecarfan]

So now that Elon’s presentation is over, I have some questions and observations:

The CGI images and the new Starship video show that the base of the vehicle is flattened on the windward side in a way I had not noticed before, and there are now two stubby protrusions at the base on the leeward side. I didn’t see any on the windward side.

I didn’t see where the Starship landing legs will be located.

The launch structure/tower now has the base of the vehicle far above the ground. I don’t recall seeing that before. I would guess that the launch tower will contain a lifting crane to hoist the entire vehicle up to the launch platform, but why have that platform so far above the ground? Is it then easier to handle the exhaust at launch because a massive flame trench like the Saturn V needed is no longer required?

The LZ is shown right next to the launch tower. If that is the way it will be in real life that shows a tremendous amount of confidence on SpaceX’s part. I assume being that close is desirable because the tower crane (my speculation) can then reach out and lift the vehicle back onto the launch pad where it will then be refueled.

It is unclear to me how the Super Heavy/Starship will be moved from the horizontal to a vertical orientation. Apparently it will not be the same way the F9 is handled.

I wonder if a new HF building is going to be constructed next to the existing building.

 

[Grendal]

So now that Elon’s presentation is over, I have some questions and observations:

The launch structure/tower now has the base of the vehicle far above the ground. I don’t recall seeing that before. I would guess that the launch tower will contain a lifting crane to hoist the entire vehicle up to the launch platform, but why have that platform so far above the ground? Is it then easier to handle the exhaust at launch because a massive flame trench like the Saturn V needed is no longer required?

The LZ is shown right next to the launch tower. If that is the way it will be in real life that shows a tremendous amount of confidence on SpaceX’s part. I assume being that close is desirable because the tower crane (my speculation) can then reach out and lift the vehicle back onto the launch pad where it will then be refueled.

It is unclear to me how the Super Heavy/Starship will be moved from the horizontal to a vertical orientation. Apparently it will not be the same way the F9 is handled.

Launch tower is higher because of the exhaust from launch.

Lifting crane on tower as seen in earlier videos - yes.

Always vertical. No horizontal at all. Being horizontal would probably damage the rocket - maybe. On second thought, there are big stresses horizontally coming into the atmosphere.

How about the spiral building design in the future - very cool. Definite improvement too.

 

[mongo]

Mk1 is 200 mT, 80 mT over their 120 mT target

Yes, the first prototype is over target mass. However, that does not mean the design concept is flawed. From tonight presentation, they are staying with150 tons to LEO and will get the mass down on subsequent builds. I believe Elon also stated stainless was the lightest option on a full system basis.

Reusing the second stage inevitably brings in a bunch of aerodynamic issues (because you're basically doing a full reentry), limiting usable payload and increasing complexity/risk.

Are you not planning on going to Mars? Limiting yourself to a return capsule only?

As to payload, Starship will have the highest payload of any rocket ever. Hardly a limiting factor. Full reuse means it is cheap to operate. So cheap infact that SpaceX is planning to retire FH and F9.

The real revolution is in-orbit refueling via a depot. Starship Heavy, with a simple and inexpensive expendable second stage, would work wonders at this.

FH has max LEO payload of 70 tons, less than half of Starship. So twice the flights. Plus needing to reintegrate after each launch. It also runs on more expensive fuel and pressurization gas.
Throwing away the second stage means each Tanker equivalent trip costs >$19 million extra not counting fairing recovery. Cost calculation for Falcon 9 & Falcon Heavy : spacex

The revolutions are Raptor for capibility, reusability for cost, and refueling for range.